Hello
look on GET DIAGNOSTIC statement or FOUND variable
CREATE OR REPLACE FUNCTION foo()
RETURNS boolean AS $$
BEGIN
SELECT INTO temp_table ...
RETURN found;
END;
$$ language plpgsql;
regards
Pavel Stehule
2009/5/18 Joshua Berry <yoberi@gmail.com>:
> Hello all,
>
> Is there an easy and efficient way to return a boolean false for a query
> that returns no result, and true for one that does return a result?
>
> Currently we select the result into a temp table.
>
> SELECT INTO temp_table id FROM ... ;
> IF temp_table IS NULL THEN
> resp:= 'NO';
> ELSE
> resp:= 'YES';
> END IF;
>
> I'd like to combine this into one step like this:
> SELECT
> CASE
> WHEN id is null THEN 'NO'::text
> ELSE 'YES'::text
> END
> FROM ...;
>
> But, this is not have SELECT's work, I suppose. The CASE is never
> encountered when there is no result, so in the "NO" case, NULL is returned.
>
> Any hints/tips? Is our original solution okay, or is there something we can
> do to improve things?
>
> Thanks,
>
> Joshua Berry
>
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